Fire behaviour of upholstered furniture component materials at multiple scales
Sammanfattning: In this research, both experimental test methods and computer models were used to characterise the thermal decomposition processes of selected upholstered furniture component materials, namely; flexible polyurethane foam and a range of different fabric coverings. This was first done at some of the smallest, simplest levels available, and how these materials were tested and the methods chosen to investigate them, was examined. Results here already showed the importance of thorough material characterisation and how sensitivity analysis on the chosen research tools can give the researcher a much better knowledge base to begin further studies. A direct result of this was the production of one of few full factorial analyses within fire research used to characterise the influence of test input on the experimental outcomes.From there, the obtained material characterisation parameters were used to move up the scale in both size and material complexity and investigate how this acquired knowledge from a previous lower scale can be used to predict the fire behaviour as the complexity was increased. Modelling was used to simulate material fire behaviour at a larger scale based on the model input parameters obtained at a previous simpler scale. Additionally, extended experiments, at the larger scales, were performed to act as validation for the models, but were also used to investigate the effects of increasing complexity. One of the outcomes from this work was the development of new or modified testing methods that were designed to provide new knowledge on smoke development, and improve the ability to use fire test outcomes as a means of model validation for the scaling process. Furthermore, investigations at the middle scale highlighted complex interactions when different materials (e.g. foam core and fabric cover) were combined to form a composite product. The form of interaction was also dependent on the type of fabric used, and these interactions were found to be unpredictable based on previous lower scale data.Finally, the larger scales were investigated experimentally through a series of large-scale, multi-dimensional test series. These test series, aimed to be the last rung in the scaling ladder for this study, and highlighted a number of weaknesses or limitations in the scaling methodology. These limitations were predominately about influencing factors that could not be investigated through lower scale research, thus highlighting the need in fire science for both bottom-up (i.e. scaling methods) and top-down (i.e. large scale experiments) research methods in order to get a more comprehensive knowledge base on material fire behaviour and contribute to increasing the overall fire safety of our world.
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